hickory shad restoration in three maryland rivers · 2020. 7. 29. · hickory shad restoration in...

Hickory Shad Restoration in Three Maryland Rivers

F-57-R Segment 20 Progress Report

Reporting period January 1, 2018 to June 30, 2019

Charles P. Stence*

Matthew W. Baldwin

Ashlee N. Horne

Charles E. Yetter

Maryland Department of Natural Resources

Fishing and Boating Services

301 Marine Academy Drive

Stevensville, MD 21666

*Corresponding author: [email protected]

***Reporting Timeline***

This progress report will cover calendar year 2018 sub-projects one, two, three and overall

restoration progress. Elements of the project initiated in 2019 will be briefly reported on. A

comprehensive progress report for 2019 will be submitted in 2020.

OUTLINE

1. Need

2. Objective

3. Expected Results and Benefits

4. Approach

5. Justification to amend approach 2017

6. Location

7. 2018 Sub-Project 1- Produce, mark and stock cultured Hickory Shad.

a. Objectives

b. Materials and Methods

i. Broodstock Collection

ii. Hormone Induced Ovulation

iii. Egg Culture

iv. Marking

v. Larval Stocking

vi. Early Juvenile Stocking

vii. Stocking Goals

c. Results and Discussion

i. Hickory Shad Tank Spawn Production Summary

ii. Stocking Summary

d. 2019 Sub-Project 1 - Preliminary Results - Work In Progress

8. 2018 Sub-Project 2 - A. Assess the contribution of hatchery-produced fish to the

resident/pre-migratory stock in the Patapsco River. B. Monitor the abundance and

mortality of larval and juvenile shad using marked hatchery-produced fish.

a. Objectives


i. CPUE and Geometric Mean

ii. Mortality and Abundance Estimates


i. Patapsco River


9. 2018 Sub-Project 3 - Estimate the contribution of hatchery origin Hickory Shad to the

adult spawning population and monitor recovery of naturally produced stocks.

a. Objectives


i. Survey Locations

ii. Catch Per Unit Effort Analysis

iii. Origin Composition (Hatchery vs. Wild)

iv. Virgin and Repeat-Spawning Compositions


i. Patapsco River Adult Hickory Shad Spawning Stock

1. Patapsco River Hickory Shad CPUE

2. Patapsco River Hickory Shad Origin Composition (Hatchery vs.

Wild)

3. Patapsco River Hickory Shad Virgin and Repeat-Spawning

Compositions

4. Patapsco River Hickory Shad Spawning Stock Discussion


10. Susquehanna River (Brood Source) Hickory Shad Spawning Stock

11. 2018 Overall Restoration Progress

a. Patapsco River

b. Patuxent River

c. Choptank River

12. Literature Cited

Need

Hickory Shad Alosa mediocris were historically abundant in many Chesapeake Bay

tributaries (O’Dell et al. 1975, 1978). Populations declined similar to other Clupeid species

during the 1970s (Minkkinen 1999). A moratorium was enacted on all Maryland Hickory Shad

harvest in 1981. Recently, some upper Chesapeake Bay tributaries have experienced a mild

resurgence in Hickory Shad runs. The increased availability of Hickory Shad broodstock

provided the opportunity to culture and stock this species. Few studies have been conducted on

Hickory Shad. Funding obtained through Sportfish Restoration Act (F-57-R) has supported the

Maryland Department of Natural Resources restoration project since 1999.

Previous work conducted under F-57-R yielded new Hickory Shad spawning strategy and

life history information. Many Chesapeake Bay tributaries had historical Hickory Shad runs

equal to or greater than that of American Shad Alosa sapidissima. Since shad populations

indicate evidence of density dependent spawning behavior, self-sustaining shad populations are

not likely to return to tributaries without hatchery stocking. Since 1999 the Maryland Department

of Natural Resources has been developing spawning, culture, marking and stocking techniques

that could restore spawning populations of Hickory Shad to target tributaries. These techniques

have been continuously refined, and reintroduction of Hickory Shad to target tributaries has

progressed similar to the department’s American Shad restoration projects.

Objective

The overall objective for this proposed scope of work is to reintroduce self-sustaining

Hickory Shad populations to the Patapsco River. Stocking larval and juvenile hatchery-origin

fish should produce adult stock that will return to spawn upon maturity. The depressed native

stocks do not optimally utilize the tributary. This tributary has historically supported spawning

runs.

Expected Results and Benefits

Hatchery inputs are intended to provide adult spawning stock that will produce self-

sustaining populations in the target tributary. These fish have tremendous value for stock

assessment purposes at the larval, juvenile and adult life stages, since all stocked shad receive an

otolith mark. Larval and early juvenile otolith marking is the primary identification method for

hatchery reared Hickory Shad. Natural spawn culture techniques allow for the production of

large numbers of larval and juvenile shad for stocking and assessment efforts.

Upper Bay shad populations, specifically the Susquehanna River, currently support

Hickory Shad populations that sustain active catch and release recreational fishing. Restoring

Hickory Shad stocks to tributaries that historically supported runs will increase fishing

opportunities for anglers. An indirect benefit of restoring shad populations to self-sustainable

levels is the increased prey availability provided by both juvenile and adult shad for larger, more

economically important recreational species such as Striped Bass Morone saxatilis, Bluefish

Pomatomus saltatrix, and Weakfish Cynoscion regalis.

Approach

The Maryland Department of Natural Resources American Shad hatchery based

restoration project incorporated Hickory Shad into the project in 1996. The project continued

over the next three years through various short-term funding sources. In 1998 it was determined

that a long term funding source would be required, since it would take years of additional

stocking and assessment to successfully support restoration. Federal Aid in Sport Fish

Restoration funds were utilized to conduct this long-term effort.

The project consists of three sub-projects:

1. Produce, mark and stock cultured Hickory Shad.

2. A. Assess the contribution of hatchery-produced fish on the resident/pre-migratory stock

in the Patapsco River.

B. Monitor the abundance and mortality of larval and juvenile shad using marked

hatchery-produced fish.

3. Analyze the contribution of hatchery origin Hickory Shad to the adult spawning

population and monitor the recovery of naturally produced stocks.

Justification to amend approach 2017

Hickory Shad populations in the Patuxent River were deemed restored in 2007, and the

Choptank River was deemed self-sustaining in 2014. Both rivers were original target tributary

with stocking beginning in 1996. The Patuxent River watershed is heavily urban-impacted, but

has been the subject of numerous mitigation efforts due to its designation as a targeted watershed

(e.g., sewage treatment upgrades). The Choptank River watershed is rural-impacted by

agricultural activities and low urban development. Choptank River efforts included the tributary

Tuckahoe Creek. Both rivers will be sampled on a three year rotation in order to maintain trend

data. Sampling will be conducted in the spring of 2020.

In 2014, Hickory Shad were stocked in the Choptank River for the final time and a

tributary needed to be identified for stocking efforts. In 2015, the program shifted focus and

conducted exploratory surveys on the Pocomoke River, Marshyhope Creek, Chester River,

Sassafras River, Elk River, Northeast River, and the Patapsco River for baseline Hickory Shad

data in order to assess restoration need. Future target tributaries would be chosen based on

historical data, angler access, and suitable Hickory Shad spawning and nursery habitat.

Restoration efforts are now directed to the Patapsco River as a result of this assessment. The

main-stem Patapsco River is 63 km long and heavily urban impacted. With its origins in Carroll

and Howard county farm land, the Patapsco River quickly transitions to urban sprawl and the

tidal portion creates the Baltimore Harbor. The river was once impacted by industry and dams. A

Baltimore City drinking reservoir is in its north branch. Union Dam and Simkins Dam were

removed in 2010 and 2011 respectively, and the lowermost dam, Bloede Dam was removed in

2018. Once the Bloede Dam was removed, anadromous species had access to more than 104 km

of the river and its many tributaries. As of 2018 only one dam (Daniels Dam) remains in the

main-stem.

From 2012-2017 the Patapsco River was the subject of a separate restoration effort

known as the Patapsco River Shad and Herring Restoration Project. American Shad and Hickory

Shad were stocked by the Maryland Department of Natural Resources. The United States Fish

and Wildlife Service (USFWS) Maryland Fish and Wildlife Conservation Office (MDFWCO)

was subcontracted to perform assessments. This project was funded by a six year grant from the

Maryland Department of Transportation (MDOT) through the Maryland Port Authority (MPA).

Recent Patapsco River fish passage implementation has reopened historical spawning

habitat for anadromous species such as American Shad, Hickory Shad, Blueback Herring Alosa

aestivalis and Alewife Alosa pseudoharengus. This tributary historically supported spawning

stocks, and reintroduction through hatchery inputs could indicate positive impacts. Restoring

Hickory Shad populations takes many years, and it was determined by project biologists that it

would be advantageous to continue the MPA funded project, given the head start the river had

received. Several years of additional inputs would be necessary to determine whether hatchery

stockings were successful.

In 2017, the USFWS Wildlife and Sport Fish Restoration F-57-R grant proposal was

amended to continue stocking and assessment on the Patapsco River. In 2018, Hickory Shad

were stocked as larvae and early juveniles in the Patapsco River, continuing the restoration effort

previously funded through the MPA grant. Since stocking in the Choptank and Patuxent rivers

ceased, it was an opportunity to continue this worthy effort.

Location

Restoration efforts will focus on the Patapsco River (Figure 1). The Patapsco River

watershed is heavily impacted by urban, commercial and industrial development, but has been

the subject of numerous mitigation efforts (e.g. sewage treatment upgrades, habit improvements,

fish passages, and dam removal).

2018 Sub-Project 1.

Objectives

“Produce, mark and stock cultured Hickory Shad.”

In 2018, the Maryland Department of Natural Resources staff produced, marked, and

stocked Hickory Shad larvae and juveniles. Hickory Shad larvae were marked and stocked into

the Patapsco River (Figure 1). Larval fish were stocked into the target tributary immediately after

being marked with a day-1 oxytetracycline (OTC) mark. Early juvenile fish were marked with

OTC on day-1 and day-3, then were stocked as larvae into hatchery ponds and later transported

to the river at approximately 30 days of age. Hickory Shad were produced through hormone-

induced tank spawning utilizing Susquehanna River origin broodstock.

Materials and Methods

Broodstock Collection

Hickory Shad broodstock were collected from the Susquehanna River (Figure 2; Table

1). Since the mid-1990s, Hickory Shad abundance increased in the upper Chesapeake Bay and its

tributaries (ASMFC 1999).

Prior to 2005, Hickory Shad broodstock were collected by hook and line, either

immediately downstream of Deer Creek or at Shure’s landing, near the base of Conowingo Dam

(Figure 2). In 2005, the Maryland Department of Natural Resources staff transitioned to boat

electrofishing to collect Hickory Shad broodstock. The sample area was located along the

western shore of the Susquehanna River, from just downstream of Deer Creek at Rock Run Mill

down to Lapidum boat ramp in the Susquehanna State Park (Figure 2). Electrofishing was used

for its ability to efficiently collect larger numbers of Hickory Shad than could be collected by

hook and line. Electrofishing for Hickory Shad broodstock requires less project staff and reduces

handling stress. During broodstock collection, immobilized Hickory Shad were netted and placed

into the electrofishing boat’s live well (220 L). The live well water was flow-thru and

oxygenated.

Hormone Induced Ovulation

Injections of Luteinizing Hormone-Releasing Hormone analog (LHRHa), a synthetic

analog of gonadotropin-releasing hormone (GnRHa), stimulate pituitary release of endogenous

gonadotropin. The use of LHRHa induces gonadal maturation, ovulation and spawning (Mylonas

et. al. 1995). In accordance with the Investigational New Animal Drug Permit (INAD #11-375-

18-003), the Maryland Department of Natural Resources purchased pre-made 75µg hormone

pellets for ovulation induction. The LHRHa pellets are sold under the product name Ovaplant®

and produced by Western Chemical Inc. (Ferndale, WA). Hickory Shad were sedated at the boat

ramp with the Investigational New Animal Drug Permit Aqui-S 20E® (eugenol; INAD# 741-19-

028F) at a rate of 10 mg/L. Males and females received an intramuscular implant of Ovaplant®

into the dorsal musculature. Implants were administered through a spring-loaded 11-gauge

multiple dose Ralogun® (Intervet/Schering-Plough Animal Health, The Netherlands).

Egg Culture

Fish were placed into circular flow, insulated 3,785 L tanks at 4.0-6.0 ppt salinity and

transported to Manning Hatchery (Figure 3). Dissolved oxygen (DO) was continuously

monitored and regulated to saturation (approximately 10.0 ppm) with a Point Four oxygen

monitoring system (Coquitlam, BC, V3K 6X9, Canada). Adults were netted from the transport

tank and into 3.05 m diameter natural spawn tank systems. A sex ratio of approximately 3:2

male: female is preferable in natural spawn systems, but there are times when males are not

sufficiently available to meet this ratio. Salinity was maintained at 2.0 ppt. A 25% water

exchange was performed each day to maintain adequate water quality. Fish spawned naturally

and eggs were automatically transported to an egg collection box through an airlift system.

Eggs were volumetrically measured (ml) and fertilization was determined 24 hours post

spawn. Eggs were placed into modified McDonald hatching jars supplied by approximately 2.0

L/min water flow. Prophylactic treatments of formalin were administered in the morning and

afternoon to control fungi. Eggs were exposed to a 600:1 treatment of formalin for

approximately 17 min. Hickory Shad eggs began hatching at day four. In order to stimulate a

simultaneous hatch, jars were removed from the egg bank, placed outdoors in sunlight for ten

minutes and stirred occasionally. The rapid temperature change, lower oxygen content,

concentrated hormonal influence and agitation stimulated simultaneous hatching. Hatching jars

were then placed on benches beside 1.5 m (1,800 L) circular flow-through larval tanks that

allowed water and larvae to flow from the hatching jars to the flow-through tanks. Water was

supplied at approximately 2.0 L/min.

Hickory Shad feed on rotifers that are difficult to culture in the Maryland Department of

Natural Resources hatchery. Therefore, Hickory Shad larvae were marked and stocked into

hatchery ponds or target tributaries prior to first feeding (<six days age). Prior to stocking, larvae

were enumerated using a volumetric direct proportion procedure in which a columnar sample of

water was collected with a 25.0 mm diameter PVC tube at random locations in the larval tank.

Larvae were enumerated in this sample and the total number of larvae in the tank was estimated

by extrapolation to the total tank volume.

Marking

All fish stocked into the target tributary were given an OTC mark to identify recaptured

fish as hatchery origin. OTC marks applied to larvae or juveniles will still be visible as adults.

Larval marks were produced by immersion in a 300 ppm buffered OTC bath for six hours.

Dissolved oxygen content was monitored and regulated (>5.0 ppm) by a carbon air stone

connected to a liquid oxygen delivery system. All water used at Manning Hatchery for OTC

marking was softened before use (Culligan ion exchange system). Reliable marking can only

take place in water with hardness below 20 mg/L and water hardness at Manning Hatchery

routinely exceeds 200 mg/L. Samples analyzed from each group of OTC marked fish indicated

that all fish stocked were successfully marked. Marks were verified by viewing larval otoliths

with an ultraviolet microscope (Zeiss Axioskop 20).

Larval Stocking

Fish intended for larval stocking were given a larval immersion OTC mark at day-1 after

hatch. Larval stocking was accomplished by placing marked larvae into boxes originally

designed for shipping tropical fish. These containers consisted of a cardboard box outer shell, an

inner insulating foam box, a black plastic trash bag to reduce stress of bright sunlight and a

double thickness plastic fish transport bag. Larval culture tanks were drawn down to crowd the

fish. Larvae were scooped out of the tanks and placed in the shipping bags/boxes, which were

supplemented with salt (1.0 ppt) to mitigate stress. Each bag was filled with pure oxygen and

sealed with electrician’s tape. Boxes were transported to the Patapsco River and the bags were

placed into the water to temperature acclimate. Once acclimated, the bags were opened and river

water was slowly introduced to further acclimate larvae to river water chemistry. Bags were then

emptied into flowing water to minimize predation.

Early Juvenile Stocking

Fish intended for early juvenile stocking were given OTC immersion marks at day-1 and

day-3 after hatch. After the second mark was administered, larvae were stocked into hatchery

ponds and cultured for approximately thirty days. Manning Hatchery, GenOn Energy, and the

University of Maryland Center for Environmental Science (UMCES) Aquaculture and

Restoration Ecology Laboratory (AREL) Horn Point provided grow out ponds to hold fish for

the restoration effort (Figure 3). The decision to take juveniles out of the pond was based on

zooplankton density. Food availability was evaluated with a plankton net. Early juveniles were

removed from culture ponds when food availability declined substantially.

Juvenile fish tend to stress easily and direct netting from hatchery ponds into transport

tanks results in unnecessary mortality. To prevent losses, juvenile fish were concentrated within

the grow out ponds, using a seine net 61.0 m long, 3.1 m deep, with 6.4 mm stretch mesh. They

were then effectively removed by scooping the concentrated schools of fish out with buckets and

were poured into the transport tanks. A small one-horsepower water pump was used to create

current within the seine net to orient shad into the water flow. This current serves two purposes.

Shad concentrate into dense schools at the water’s surface, which allows them to be easily

bucketed, and it separates the fish from algae and detritus. The use of the pump has resulted in

high early juvenile survival rates, due to the reduction of algae and detritus in the transport tanks.

Early juveniles were transported in fish hauling tanks at 3.0-5.0 ppt. salinity and saturated DO to

mitigate stress. Ponds at GenOn Energy and UMCES-AREL already have natural salinity of 6.0-

8.0 ppt.

A one-horsepower trash pump was also carried on the stocking truck to temper juvenile

shad before stocking. Fish were tempered until temperature and salinity in the tank were within

one degree Celsius and 1.0 ppt salinity of the river value. Although this adds a considerable

amount of time that fish are aboard the transport truck, it is assumed this procedure increases the

survival of early juvenile stocked shad by reducing stress. Juvenile stocking was accomplished

by quick-dumping marked juveniles through a quick release drain hose, with a diameter of 15.0

cm, directly from the transport vehicle into the river.

Stocking Goals

The project developed stocking goals (Table 2) based on previous experience with larval

survival. Stocking multiple life stages gives fisheries managers the ability to assess larval

survival and estimate juvenile mortality and abundance of each life stage. Larval stocked fish can

efficiently contribute large numbers of juveniles if survival is high. The stocking goal for the

Patapsco River was set at 500,000 larvae.

Fish stocked as early juveniles survive extremely well and are young enough to

successfully imprint to the target tributary. Stocking early juveniles can also mitigate the impacts

of poor larval survival since post-stocking survival of this life stage is high. In 2018, Hickory

Shad early juveniles were stocked into the Patapsco River. The project developed stocking goals,

which were based on past experience with juvenile survival. The stocking goal for the Patapsco

River was set at 75,000 early juveniles.

Results and Discussion

Hickory Shad Tank Spawn Production Summary

Hickory Shad overall fertilization was 41.8% in 2018 (Table 3). From the time of the

program’s inception, Hickory Shad fertilization rates have decreased at a linear rate (F1,20 = 6.84,

p = 0.017), with an R2 of 0.2592 (Figure 4). 2018 fertilization rate was above the linear average.

Hickory Shad egg fertilization rates (Figure 4) fluctuate from year to year and it remains difficult

to pinpoint an exact cause for the overall trend of declining fertilization success.

Egg clumping in hatching jars has always been an issue and primary concern, but may

not explain the decreasing fertility trend. Hickory Shad eggs are adhesive and will attach to

anything they come in contact with, including other eggs. Egg clumping increases larval

entrapment within hatching jars, which reduces hatching success and lowers overall larval

survival. Egg de-adhesion techniques were investigated extensively, and one technique has

proved to be moderately effective, but no perfect solution has been found. Egg de-adhesion

techniques were adapted from methods described for Atlantic Sturgeon (Mohler 2003). Eggs

were treated with solutions containing fuller’s earth and tannic acid. De-adhesion solutions

containing 100-200 g of fuller’s earth and 50-75 mg of tannic acid per gallon of water were used.

Eggs were gently mixed in the de-adhesion solution for 20 minutes with a large feather. The egg

de-adhesion solutions were effective one to two days after treatment, then eggs would clump

together again. The agitation of eggs with a large feather in the hatching jars several times per

day helped to minimize the clumping and caking of eggs prior to hatching. Excess iron in the

hatchery water may be a contributing factor as well.

Stocking Summary

A summary of 1996-2018 Hickory Shad stocking production appears in Figure 5. In the

early years of restoration efforts, larvae and late juveniles were the only life stages stocked into

the target tributaries. In 2001, early juveniles were cultured in hatchery ponds and stocked 30

days later into the Patuxent River. In 2002, juveniles were cultured and stocked into the Patuxent

River, Choptank River and Marshyhope Creek. Hickory Shad stocking was suspended in the

Patuxent River in 2008 and Marshyhope Creek in 2010 to focus project resources towards

stocking the Choptank River. In 2014, Hickory Shad stocking concluded on the Choptank River.

The stocking effort resulted in the formation of a stable population. Surveys were conducted in

2016 and 2017 on the Pocomoke River, Marshyhope Creek, Chester River, Sassafras River, Elk

River, Northeast River, and the Patapsco River for baseline Hickory Shad data in order to

determine restoration opportunities. In 2018 after two years of surveying possible target

tributaries, it was determined that stocking would focus on the Patapsco River. The decision was

partially based on survey results, historical data, angler access, nursery habitat and suitable

habitat for Hickory Shad spawning.

The Patapsco River also had two other factors that were taken into consideration. The

removal of Bloede Dam, the lowest dam on the Patapsco River, was scheduled to be completed

by 2019. The removal of the Bloede Dam would open up miles of potential spawning habitat for

returning Hickory Shad adults. Secondly, the Patapsco River Shad and Herring Restoration

Project grant funded by the MPA ended when funding expired. The Maryland Department of

Natural Resources had been providing juvenile Hickory Shad for this short term project since

2013 (Table 4). Restoring Hickory Shad populations takes many years, and it was determined

that it would be advantageous to continue the project efforts, given the head start the river had

received.

The Patapsco River Shad and Herring Restoration Project was part of a compensatory

mitigation package designed around the Masonville Project. The Masonville Project is a Dredged

Material Containment Facility (DMCF) located in Baltimore Harbor. The Masonville Cove

Environmental Education Center and a 22-hectare Conservation Area was constructed adjacent

to the DMCF in 2009 as part of the mitigation. As a component of the DMCF project, the MPA

was required to develop a mitigation project to offset impacts associated with filling

approximately 53 hectares of open water in the Patapsco River. The USFWS MDFWCO was

subcontracted to perform monitoring activities of stocking efforts, including field sampling and

collections, laboratory sample preparation and interpretation, data analysis, and report writing.

Hickory Shad broodstock collection for Patapsco River shad production was conducted on the

Susquehanna River in conjunction with broodstock collection for Choptank River stockings

under the F-57-R grant. Grant costs were appropriately accounted for by project to ensure that

charges were apportioned between the two funding sources.

In 2018, Hickory Shad larvae (915,000) were stocked at the Rt. 648 Bridge location on

the Patapsco River. Hickory Shad early juveniles (85,000) were stocked at the Southwest Area

Park (SWAP) boat ramp on the Patapsco River (Figure 6, Table 2). 2018 stockings are separated

by event in Table 5. Historical Hickory Shad stocking production for all years by tributary is

contained in Tables 6 through 10. Some larvae were previously stocked into the Patapsco River

(1998-2001) to investigate fish passage issues. Additionally, excess marked larvae were stocked

into the Chester River in years when the timing of culture and marking activities precluded

stocking into the target tributaries. All Hickory Shad cultured and stocked since the inception of

the program can be viewed in Tables 6 through 10.

Hickory Shad larval stocking numbers and early juvenile stocking numbers met project

goals in 2018 (Table 2; Table 4).

2019 Sub-Project 1 – Preliminary Results – Work in Progress

Analysis of the data for 2019 is currently in progress. Adult Hickory Shad were caught by

electroshocking boat on the Susquehanna River on 22 April and 24 April 2019 for broodstock

collection. A total of 168 Hickory Shad were used in spawning culture tanks at Manning

Hatchery. Approximately 9.54 million eggs were produced, with a fertilization rate of 46.09%,

and 1,725,000 larvae and 5,000 early juveniles were stocked.

The complete analyses and summary of the data collected in 2019 to produce, mark and

stock cultured Hickory Shad in the Patapsco River will appear in the next F-57-R Segment 21

Progress Report.

2018 Sub-Project 2

Objectives

Restoration stocking of Hickory Shad in the Choptank and Patapsco rivers began in 1994

and 2012, respectively. Choptank River summer juvenile seine survey commenced in 1996 and

the Patapsco River summer seine surveys began in 2013. Both surveys had a goal to collect

juvenile Hickory Shad to determine the success of the stocking program in each river. From 2013

to 2017, and MPA funded grant supported restoration activities in the Patapsco River and all

fisheries monitoring was conducted by USFWS Maryland Fish and Wildlife Conservation Office

(MDFWCO). In 2018, the Patapsco River was added to the Maryland Department of Natural

Resources’ Wildlife and Sport Fish Restoration grant to continue the project for stocking and

assessment

Two quantifiable population variables were identified to evaluate restoration progression

of juvenile Hickory Shad in the targeted rivers.

A. “Assess the contribution of hatchery-produced fish to the resident/pre-migratory stock

in the Choptank River and Patapsco River.”

B. “Monitor the abundance and mortality of larval and juvenile shad using marked

hatchery-produced fish”.


The Patapsco River was sampled with a seine 30.5 meters long, 1.2 meters deep, with

6.4mm stretch mesh. The net was deployed by hand from shore into deep water and back to

shore at established seine sites. Any juvenile Hickory Shad collected from the seine were placed

into plastic bags, labeled, and stored on ice. Upon return to the lab, the samples were frozen to -

9°C. All bycatch species data was recorded.

Sagittal otoliths are removed from each Hickory Shad captured from the Patapsco River.

Otoliths are mounted on 76.2 mm x 25.4 mm glass slides with Crystalbond 509 (Aremco

Products, Ossining, NY).

Mounted otoliths are lightly ground on 600 grit silicon carbide wet sandpaper and viewed

under an LED epifluorescent light at 400X magnification at 50-100 watts with a Zeiss Axioskop

20 microscope. The presence and location of an OTC mark epifluorescence is recorded.

Epifluorescence is a technique in which transmitted light in the wavelength of 490-515 nm is

allowed to strike the specimen. The specimen then absorbs this light energy and reflects light of

a longer wavelength back through the microscope objective.

CPUE and Geometric Mean

The juvenile index is described by calculation of a catch per unit effort (CPUE). It is

defined as the number of captured juvenile Hickory Shad divided by the number of seine hauls

completed. Indices of relative abundance are presented as the total arithmetic mean (AM) catch

per haul and geometric mean (GM) catch per haul. The GM has been adopted by the Atlantic

States Marine Fisheries Commission (ASMFC) as the preferred index of relative abundance. The

GM is a more precise statistical tool for handling these data because it is not as sensitive to a

single large sample value. Hickory Shad, like American Shad, are schooling fish and

theoretically subject to these types of captures with a large seine net. Since the inception of this

project, Hickory Shad CPUE has been used to quantify indices of relative abundance. As a

bridge between previous F-57-R progress reports, the 2008 report indicated AM and GM. All

indices of relative abundance from 2009 on are now reported as GM only.

Mortality and Abundance Estimates

In addition to providing future broodstock, juvenile stocking is valuable as a pre-

migratory stock assessment tool through use of a multiple marking technique. Hatchery stocking

is also used to evaluate the efficacy of stocking different life stages and the eventual impact to

the returning adult population.

There are assumptions made when using these types of estimates as described by (Ricker

1975):

● The marked fish suffer the same natural mortality as the unmarked fish.

● The marked fish are as vulnerable to capture as are the unmarked fish.

● The marked fish do not lose their mark.

● The marked fish become randomly mixed with the unmarked; or the distribution of

fishing effort (in subsequent sampling) is proportional to the number of fish present in

different parts of the body of water.

● All marks are recognized and reported on recovery.

● There is only a negligible amount of recruitment to the catchable population during the

time of recoveries are being made.

Estimates of juvenile abundance, mortality and survival were derived from the following

formulas.

Larval survival to juvenile stocking was calculated by (Ricker 1975):

𝑆1 =(𝑅12) 𝑀2

(𝑀1) 𝑅22

Variance 𝑆1 = 𝑆12{(

1

𝑅12) + (

1

𝑅22) − (

1

𝑀1) − (

1

𝑀2)}

where M1 is the number of fish marked at the start of the first interval (larval stocking), M2 is the

number of fish marked at the start of the second interval (early juvenile stocking), R12 is

recaptures of larval marked fish in the second interval (after early juvenile stocking), R22 is

recaptures of early juvenile interval marked fish in the second interval or (after early juvenile

stocking), and S1 is the survival rate of larvae during interval one (from the time of marking

larvae in interval one to time of marking early juveniles in interval two).

Instantaneous mortality is derived from survival estimates and is used in conjunction with

stocking data to calculate juvenile abundance:

𝑍 =− 𝑙𝑛 𝑙𝑛 𝑆1

𝑖𝑛𝑡𝑒𝑟𝑣𝑎𝑙

Where Z is instantaneous mortality rate and S1 is survival rate.

Abundance of juvenile shad prior to out migration was also calculated by Chapman’s

modification to the Peterson estimate (Ricker 1975):

𝑁 ={(𝐶 + 1)(𝑀 + 1)}

𝑅 + 1

where N is the population estimate, M is the number of marked fish stocked, C is the number of

fish examined for tags (total captures) and R is the number of marked fish that were recaptured

(larval or early juveniles).

From Ricker (1975): Calculation of 95% confidence limits based on sampling error using

the number of recaptures in conjunction with Poisson distribution approximation.

Chapman’s modification (1951):

𝑁∗ ={(𝐶 + 1)(𝑀 + 1)}

(𝑅 + 1)

Where R1 is from Pearson’s formula to calculate upper and lower limits:

𝑅1 = 𝑅 + 1.92 ± 1.960√𝑅 + 1.0


Patapsco River

No juvenile Hickory Shad were collected by seine from the Patapsco River in 2018.

Juvenile Hickory Shad are difficult to recapture with seine gear. Very few Hickory Shad have

been captured over the years in any previous restoration work. Juveniles are generally larger in

size than American Shad, well developed, and have the ability to avoid sampling gear. Until

juvenile Hickory Shad are captured in sufficient numbers, calculation of geometric mean and

mortality and abundance estimates are not possible. Currently, adult Hickory Shad assessment is

a better indicator of restoration progress (Sub-Project 3).

2019 Sub-Project 2 - Preliminary Results - Work In Progress

No juvenile Hickory Shad were collected by seine from the Patapsco River in 2019.

2018 Sub-Project 3

Objectives

Patuxent River and Choptank River spawning ground surveys commenced in 1999 to

collect adult Hickory Shad. Restoration stocking of Hickory Shad began in 1996 on these

targeted rivers (Figure 7). In 2008, Patuxent River composition of wild adults indicated a stable

population and wild adults exceeded 80% for three consecutive years, so hatchery stocking was

suspended. The composition of wild adults in the Choptank River was also stable and exceeded

75% for three consecutive years, so hatchery stocking was suspended in 2015. The Patapsco

River was considered for possible restoration in 2013 and added as a target tributary for the F-57

restoration effort in 2018 (Figure 1).

Three quantifiable population variables were identified to evaluate restoration

progression and relative abundance of adult Hickory Shad spawning stocks in the targeted

tributaries. A fourth objective is to evaluate the population status of Hickory Shad spawning

stocks from brood source tributaries.

1) Estimate catch-per-unit effort (CPUE) in each target river using geometric mean.

2) Estimate the contribution of hatchery produced fish to the adult spawning

populations.

3) Estimate the frequency of virgin and repeat-spawning.

4) Monitor the viability of the Susquehanna River as a Hickory Shad brood source

through analysis of virgin and repeat-spawning compositions.


Survey Locations

Based on the stable population observed in the Patuxent and Choptank rivers, there is no

longer a need to survey the rivers every year. Surveys are conducted every three years to

maintain trend data.

Hickory Shad were sampled in the Patapsco River in 2018. Adult sampling was

conducted by the Maryland Department of Natural Resources’ Maryland Biological Stream

Survey (MBSS) using a 4.2 m jon boat with a 2,000 watt generator powering a Smith-Root 1.5

KVA electrofisher in the upper, non-tidal portion of the study area, and by this project using a

Smith-Root electrofishing boat SR18-E (Vancouver, WA) in the lower, tidal portion of the study

area. The upper section of the river was sampled at three river reaches (Figure 8), and the lower

section was sampled at two river reaches (Figure 9).

Sampling was conducted at historical Hickory Shad spawning areas described by

anecdotal data and concentrated in river reaches where shad were encountered during previous

sampling efforts conducted by the USFWS MDFWCO as part of the Masonville mitigation

project (Table 11). The survey was accomplished with three people, one person piloting the boat

and two people netting shad from the bow. The survey was sampled in an upstream to

downstream direction with constant voltage applied to the entire reach. Total pedal time (s) was

recorded to calculate relative abundance (CPUE). Water temperature (◦C), dissolved oxygen

(ppm), and conductivity (µS/cm) were obtained using a YSI Pro 2030 water quality meter

(Yellow Springs, OH).

The Patapsco River sampled by this project was divided into two sections. The first

section “upstream” includes the area from the wastewater treatment plant located just west of

Maryland Rt. 648 to approximately 1.44 km downstream to I-895. The second section

“downstream” begins 0.37 km north of I-895 and continues downstream 1.47 km to the bridge at

West Patapsco Avenue.

Maryland Biological Stream Survey sampled three portions of the non-tidal freshwater

region of the Patapsco River (Figure 8). Site 591 is from 200 m above Deep Run to 200 m below

Stony Run, 0.63 km long. Site 592 runs from Route 1, 0.59 km downstream to the Elkridge

Furnace Inn. Site 593 is in the Bloede Dam tailrace.

It is likely that shad utilize tidal freshwater areas downstream of our collection sites, but

increasing river width, depth and increased conductivity reduces capture efficiency with

electrofishing gear. Additionally, anecdotal evidence indicates that substantial spawning habitat

and fish movement also exists upstream of currently sampled stream reaches, but sampling

upstream habitat is limited by electrofishing boat access. In 2013-2017 surveys by the USFWS

MDFWCO and MBSS, sufficient numbers of Hickory Shad were captured in the current sample

reaches to perform analysis.

A sub-sample of 20 Hickory Shad was collected per day for age, composition and

spawning attempt analysis. All other observed shad were counted to calculate CPUE. Fish

collected were measured for total length (TL; mm), fork length (FL; mm) and sex was

determined. Scale samples were taken for age estimation and spawning mark interpretations.

Otoliths were extracted to determine hatchery origin adult composition. Shad scales were

cleaned, mounted between glass slides, and age was estimated and spawning attempts were

counted using a microfiche reader. Two biologists interpreted the scales independently. In cases

where readers disagreed on an age estimate, a consensus age was used as the final age. Scales

were aged using methods described by Cating (1953).

Catch Per Unit Effort Analysis

In an effort to standardize data collection, bracketing CPUE data began in 2011. With this

methodology, sampling will begin each year before Hickory Shad return and continue until zero

Hickory Shad are captured at the end of the spawning run. This will ensure that biologists

sampled the area throughout the entire duration of the spawning run and will reduce sampling

bias.

The GM has been adopted by this project as the preferred index of relative abundance to

evaluate stock status and restoration progress. The GM is calculated from the loge(x+1)

transformation, where x is the number of Hickory Shad encountered per shock time (min).

Beginning and ending zeros are omitted from the analysis. One is added to all catches in order to

transform zero catches, because the log of zero does not exist (Ricker 1975). The one is then

removed to accurately represent the GM data. Since the loge-transformation stabilizes the

variance of catches (Richards 1992), the GM estimate is more precise than the arithmetic mean

(AM), and is not as sensitive to a single large sample value. The GM is almost always lower than

the AM (Ricker 1975). The GM was calculated independently for each of the five sample sites.

Origin Composition (Hatchery vs. Wild)

The percentage of hatchery versus wild origin Hickory Shad adults sampled on the

spawning grounds provides insight into the impact to the adult population of stocking larval and

juvenile shad. The presence of adult hatchery origin fish on the spawning grounds early in

restoration may stimulate annual natural production. As restoration efforts continue, a transition

from a high proportion of hatchery origin fish to a high proportion of wild fish year after year

indicates natural reproduction events leading to successful recruitment to the spawning

population. Observation of changes from mostly hatchery contribution to a population dominated

by wild origin adults is a good indication of whether or not hatchery contributions are having a

substantial effect upon the adult spawning stock population.

Virgin and Repeat-Spawning Compositions

A third estimator uses analysis of virgin and repeat-spawning compositions. The number

of spawning migrations by an individual fish can be determined through examination of Hickory

Shad scales. The composition of virgin and repeat-spawn frequency observed on the spawning

grounds provides additional insight into population stability and recruitment. Low levels of

virgin-spawners may indicate problems associated with juvenile recruitment to the adult stock, or

poor spawning success. Conversely, a high level of virgin-spawners usually indicates successful

recruitment of individual year classes to the adult spawning stock. A substantial contribution of

virgin-spawners and several repeat-spawning classes utilizing the spawning grounds year after

year is indicative of a stable spawning stock.


Patapsco River Adult Hickory Shad Spawning Stock

Sixty-one Hickory Shad were observed on the Patapsco River in 2018, but only 36 were

collected. Hickory Shad were collected for length, sex, otolith and scale analysis. Twenty-one

Hickory Shad were collected by MBSS in the upstream reaches of the Patapsco River from 21

February to 24 May when water temperature ranged from 3.4°C to 22.2°C. In the lower reaches,

this project collected 15 Hickory Shad from 12 April to 31 May when water temperature ranged

from 9.1°C to 22.0°C (Figure 10).

Patapsco River Hickory Shad CPUE

The mean relative abundance (GM) for Hickory Shad on the Patapsco River was

calculated for each of the samples sites independently (Table 12). Site 592, which was sampled

by the MBSS, had the highest GM at 0.49 fish/min. The uppermost MBSS site (593) and the

downstream site sampled by this project both indicated a GM of 0.00 fish/min.

Patapsco River Hickory Shad Origin Composition (Hatchery vs. Wild)

In 2018, 36 Hickory Shad were captured in the electrofishing survey on the Patapsco

River. Origin was determined on 34 of the samples by examining OTC marks. The samples

comprised one larval hatchery origin (3%), 16 early juvenile hatchery origin (47%) and 17 wild

origin (50%) Hickory Shad (Table 13). The two samples where origin could not be determined

was due to the sample being lost or destroyed during processing.

Patapsco River Hickory Shad Virgin and Repeat-Spawning Compositions

Thirty-six Hickory Shad scale samples were collected in 2018. All of the 36 scale

samples collected were successfully analyzed and used to determine the annual spawning attempt

composition. The 2018 sample population consisted of 31% virgin spawners, 19% second-time

spawners, and 50% third-time spawners (Table 14).

Patapsco River Hickory Shad Spawning Stock Discussion

Survey results for 2018 indicate that the Patapsco River supports a wild Hickory Shad

population and hatchery inputs are supplementing the stock. Hatchery and wild origin adult

Hickory Shad were present in both the virgin and second-time spawning groups. Hatchery origin

fish with more than two spawning attempts would not be encountered based on when stocking

was initiated. Ideally, wild populations would indicate additional spawning groups returning,

however, sample sizes were small, and these spawning groups may have been missed. The

presence of wild virgin spawners indicates this population is sustaining itself at a very low level.

Hatchery stocking of early juveniles appears to be successful. Of the adult Hickory Shad

successfully examined for OTC marks, 16 of 17 (94%) were of early juvenile origin. This

suggests that larvae stocked into the Patapsco River did not successfully recruit to the 2018

sample population. Spring rains in this urban system cause the gauge height and river flow to rise

and fall rapidly during the period when larvae are being stocked. It is likely they are being

flushed from the system during heavy flows. Project biologists may search for alternative

stocking locations that provide protection from high spring flows.

The absence of Hickory Shad at both the upper and lowermost sample narrows the

location where Hickory Shad spawning may be occurring on the Patapsco River (Figure 8). The

GM at Site 592 (middle MBSS site) was four times as high as Site 591 (lower MBSS site) and

the upstream site by this project (Figure 9). It is likely that fish caught in these areas are

transient, and spawning is occurring near Site 592 (Table 12). In addition, beginning zeros were

not obtained for Hickory Shad in the 2018 sample period. Due to the high capture rate during the

first sampling week, it is likely that a large portion of the Hickory Shad run was missed, which

caused the 2018 GM to be underestimated. A more robust analysis of GM will occur when the

dataset is larger.

2019 Sub-Project 3 – Preliminary Results – Work in Progress

Electrofishing surveys were conducted on the Patapsco River for 12 weeks from 21

March to 10 June 2019. Thirty adult Hickory Shad were captured and retained for scale age and

otolith analysis. A complete analysis of CPUE, origin composition and repeat spawning analysis

will be available in the 2020 F-57-R progress report.

Susquehanna River (Brood Source) Hickory Shad Spawning Stock

The Susquehanna River Hickory Shad population has been the sole brood source for

restoration efforts (Figure 2). This population declined along with other Chesapeake Bay

Hickory Shad stocks during the 1970s, but experienced resurgence during the 1990s as a

dominant year class appeared in 1993. This year class provided a sufficient source of broodstock

adults when they began to return as spawning adults in 1996 (Minkkinen et.al. 2000). Strong and

stable Hickory Shad spawning runs have occurred since 1996, and have been sufficient to

support broodstock collection and a large catch-and-release recreational fishery.

Analysis of spawning attempt data indicate a spawning population that naturally recruits

several spawning year classes to the spawning grounds annually (Table 15). In 2018, 40 Hickory

Shad scale samples were collected for spawning composition analysis. All samples were

analyzed successfully. A consistent pattern has occurred for several years, as 4+ substantial

spawning year classes recruit every year.

Reduced stocking goals results in fewer sampling days (two days in 2018) needed to

collect broodstock. As a result, fewer samples are being collected than in the past, which

potentially results in less robust age and repeat spawn analysis. In future years, additional

samples should be collected daily to increase sample size and minimize the potential for missed

year classes.

2018 Overall Restoration Progress:

Patapsco River

The Patapsco River is in the early stages of the restoration effort. It is encouraging to see

wild origin adults (50%) returning to the spawning population in 2018. Hatchery stocked early

juveniles comprised (47%) of the adult population, suggesting the new pond harvesting and

stocking techniques are benefitting early juvenile survival. Most of the wild fish are from a

remnant population that existed prior to the initiation of stocking, since their estimated ages

average 4 years old. Repeat spawning analyses in 2018 indicate that 31% of returning adults are

virgin spawners, with 19% returning for the second time and 50% returning a third time. The

composition of the adult population will be monitored in the future until the wild component of

the adult population changes from mostly hatchery to mostly wild origin population. At that

point we may be able to say that the Hickory Shad population in the Patapsco River is restored to

a point that further stocking is not needed. Any further conclusions made about the spawning

stock of Hickory Shad on the Patapsco River would be premature. More inferences can be made

when a larger more robust dataset exists.

Patuxent River

In 2012, the Patuxent River was determined to demonstrate a static pattern of relative

abundance, which could indicate a population at carrying capacity. The last year of hatchery

stocking was 2007. Despite the healthy spawning populations that occurred prior to 2009, it

appears that the repeat spawning population has been in a steady decline based on sample size.

Fewer fish are returning to spawn more than twice, which is an indicator of poor spawning

population health. However the Patuxent River is susceptible to runoff and Secchi disk disc

attenuation coefficient readings near zero during the adult migration. Small sample size (n=26)

could be a contributing factor to the reduced number of repeat spawning attempts detected. If

sample size and repeat spawning attempts continue to decline through the next sample period

(2020), project biologists will determine if the Patuxent River Hickory Shad population will

require future hatchery inputs.

Choptank River

Beginning in 2010, all of the project restoration effort was focused on the Choptank

River. This was to permit maximum stocking impact and more detailed analysis of assessment

activities. The lack of Hickory Shad juvenile recaptures hinders a complete assessment of the

restoration effort, but trend data using adult electrofishing surveys demonstrated a stable

population of adult Hickory Shad. Several year-classes of repeat spawners were observed from a

robust sample size (n=137) in 2017. While not statistically significant, the GM was considerably

higher than in 2014, which was the last year the survey was conducted on the Choptank River.

This is a positive indicator of a stable population. Choptank River adults will be sampled in

2020.

Future comparison of the relative abundance estimate (CPUE) trends will be invaluable

to evaluate the success of the restoration progress on both the Patuxent and Choptank rivers. the

Maryland Department of Natural Resources staff will continue to survey these rivers on a three-

year rotational basis. Success of this program relies on future generations continuing to naturally

spawn in these rivers when hatchery inputs no longer supplement natural populations.

Literature Cited

ASMFC (Atlantic States Marine Fisheries Commission). 1999. Amendment 1 to the

interstate fishery management plan for shad & river herring. Fishery Management Report

No. 35, Washington, D.C.

Cating, J. P. 1953. Determining age of Atlantic shad from their scales. Fishery Bulletin 85,

Fishery Bulletin of the Fish and Wildlife Service, Volume 54.

Mohler, J. W. 2003. Culture manual for the Atlantic sturgeon, Acipenser oxyrinchus

oxyrinchus. U.S. fish and Wildlife Service, Hadley, Massachusetts. 70 pp.

Minkkinen, S. P., B. Richardson and R. Morin. 1999. Assessment of alosid stocking and natural

reproduction in a restoration setting, 1998 report pursuant to Federal Aid #NA86FA0330.

Minkkinen, S. P., B. Richardson and R. Morin. 2000. American Shad and Hickory Shad

restoration, 1999 report to Federal Aid in Sport Fish Restoration Act grant #F-57- R.

Mylonas, C., Y. Zohar, B. Richardson and S. Minkkinen. 1995. Induced spawning of wild

American Shad Alosa sapidissima using sustained administration of gonadotropin-

releasing hormone analog (GnRHa). Journal of the World Aquaculture Society

26(3):240-251.

O'Dell, J., J. Gabor and J. Mowrer. 1975. Survey of anadromous fish spawning areas for

Chester River drainage in Queen Anne's County. Project AFC-9-2. Maryland Department

of Natural Resources. Annapolis, Maryland.

O'Dell, J., J. Gabor and J. Mowrer. 1978. Survey of anadromous fish spawning areas for

Potomac River drainage, Upper Chesapeake Bay drainage. Project AFC-9-1. Maryland

Department of Natural Resources. Annapolis, Maryland.

Ricker, W.E. 1975. Computation and interpretation of biological statistics of fish populations.

Bull. Fish. Res. Board Can. 191:382 p.

Table 1. Maryland Department of Natural Resources 2018 Hickory Shad broodstock collection data.

Date Females Males

4/25/2018 37 55

4/26/2018 71 92

Table 2. Maryland Department of Natural Resources 2018 Hickory Shad stocking goals for the Patapsco River.

Stocking phase Stocking goal Amount Stocked

Larvae 500,000 915,000

Early Juvenile 75,000 85,000

Table 3. Maryland Department of Natural Resources 2018 tank spawn Hickory Shad egg production.

Total eggs produced 7,178,510

Overall fertilization 41.79%

Fertilized eggs produced 3,000,605

Total larvae stocked 915,000

Total juveniles stocked 85,000

Table 4. Historical stocking summary for larval and juvenile Hickory Shad in the Patapsco River since the

inception of Hickory Shad restoration efforts (including fish passage work 1997-2004).

Patapsco River Hickory Shad

Year Larvae Early Juveniles

1997 1,695,000 0

1998 250,000 0

1999 825,700 0

2000 500,000 0

2001 0 0

2002 0 0

2003 0 0

2004 542,000 0

2005 0 0

2006 0 0

2007 0 0

2008 0 0

2009 0 0

2010 0 0

2011 0 0

2012 0 0

2013 561,000 77,000

2014 538,500 73,000

2015 1,045,000 82,500

2016 580,000 35,000

2017 750,000 82,000

2018 915,000 85,000

Total 8,202,200 434,500

Table 5. Maryland Department of Natural Resources 2018 Hickory Shad stocking events in the Patapsco River.

Date Life stage Mark Number

5/3/2018 Larvae Day 1 465,000

5/3/2018 Larvae Day 1 100,000

5/5/2018 Larvae Day 1 250,000

5/6/2018 Larvae Day 1 100,000

5/30/2018 Early Juvenile Day 1, 3 65,000

6/7/2018 Early Juvenile Day 1, 3 20,000

Table 6. Maryland Department of Natural Resources annual Hickory Shad stocking production in all tributaries,

1996-2018. The juvenile category includes fish stocked as early juveniles (late June) and late juveniles (July/August)

Year Larvae Stocked Juvenile Stocked

1996 871,000 20,622

1997 10,689,000 35,982

1998 11,466,000 31,979

1999 16,825,000 4,601

2000 13,869,000 66,944

2001 4,999,679 93,645

2002 2,675,000 119,606

2003 2,310,000 118,551

2004 9,757,000 130,332

2005 4,410,000 403,000

2006 4,095,000 382,000

2007 1,700,000 211,500

2008 6,238,581 364,500

2009 2,737,636 242,000

2010 4,260,000 117,000

2011 4,399,000 143,750

2012 2,503,203 380,100

2013 560,000 471,000

2014 520,000 240,500

2015 1,045,000 82,500

2016 795,000 35,000

2017 750,000 87,000

2018 915,000 85,000

Total 108,390,099 3,867,112

Table 7. Historical stocking summary for larval and juvenile Hickory Shad in the Choptank River since the

inception of the restoration effort (1996-2014).

Choptank River Hickory Shad

Year Larvae Early Juveniles Late Juveniles

1996 125,000 0 7,963

1997 5,571,000 0 0

1998 4,991,000 0 0

1999 8,719,000 0 0

2000 5,634,000 0 38,508

2001 1,158,800 0 19,907

2002 1,050,000 25,000 0

2003 700,000 34,500 0

2004 4,090,000 42,350 0

2005 2,430,000 177,000 0

2006 1,770,000 220,000 0

2007 1,080,000 149,500 0

2008 3,028,000 225,000 0

2009 1,953,000 120,000 0

2010 4,260,000 117,000 0

2011 4,399,000 143,750 0

2012 2,503,000 380,100 0

2013 560,000 471,000 0

2014 520,000 240,500 0

Total 54,541,800 2,345,700 66,378

Table 8. Stocking summary for larval and juvenile Hickory Shad in Marshyhope Creek, a previous target tributary,

since the inception of the restoration effort (2001-2009).

Marshyhope Creek Hickory Shad

Year Larvae Early

Juveniles

Late

Juveniles

2001 1,230,000 0 0

2002 300,000 26,000 17,247

2003 500,000 17,000 18,551

2004 500,000 14,000 5,482

2005 370,000 66,000 0

2006 750,000 70,000 0

2007 100,000 25,500 0

2008 2,209,000 140,000 0

2009 785,000 122,000 0

Total 6,744,000 480,500 41,280

Table 9. Historical stocking summary for larval and juvenile Hickory Shad in the Nanticoke River since the

inception of the restoration effort (2001-2006).

Nanticoke River Hickory Shad

Year Larvae Early

Juveniles

Late

Juveniles

2001 1,230,000 0 0

2002 975,000 0 11,058

2003 625,000 11,500 0

2004 1,000,000 0 0

2005 450,000 40,000 0

2006 225,000 22,000 0

Total 4,505,000 73,500 11,058

Table 10. Historical stocking summary for larval and juvenile Hickory Shad in the Chester River since the inception

of the restoration effort (2003-2008).

Chester River Hickory

Shad

Year Larvae

2003 90,000

2004 200,000

2005 0

2006 0

2007 0

2008 602,000

Total 892,000

Table 11. Maryland Department of Natural Resources and Maryland Biological Stream Survey 2018 adult Hickory

Shad electrofishing survey starting and ending coordinates for the Patapsco River. *Site 593 has no ending

coordinates because it only occurs in the Bloede Dam tailrace.

River Starting latitude/longitude Ending

latitude/longitude

Patapsco River “upstream” 39.224738° N

-076.640593° W

39.225127° N

-076.628076° W

Patapsco River “downstream” 39.229178° N

-076.625855° W

39.239058° N

-076.616996° W

Patapsco River Site 591 39.212930° N

-076.699898° W

39.216105° N

-076.696884° W


-076.705498° W

39.213893° N

-076.702091° W


-076.760885° W *

Table 12. Geometric Mean (GM) calculated at all sites samples by the Maryland Department of Natural Resources

and Maryland Biological Stream Survey on the Patapsco River in 2018.

Site

Year Upstrea

m

Downstrea

m

591 592 593

2018 0.12 0.00 0.11 0.38 0.00

Table 13. 2018 Maryland Department of Natural Resources and Maryland Biological Stream Survey Hickory Shad

adults caught on the Patapsco River.

Date Sample # Sex Age Spawn Marks Origin

4/26/2018 2018-0001 Male 4 1 Wild

4/26/2018 2018-0002 Male 5 2 Early Juvenile



4/26/2018 2018-0005 Male 3 0 Wild

4/26/2018 2018-0006 Female 3 0 Early Juvenile



4/26/2018 2018-0009 Male 3 0 Wild

4/26/2018 2018-0010 Female 5 0 No Sample


5/3/2018 2018-0012 Male 3 0 Wild

5/3/2018 2018-0013 Female 4 0 Wild

5/3/2018 2018-0014 Male 3 0 Wild


5/3/2018 2018-0016 Female 5 2 Wild

5/3/2018 2018-0017 Male 4 1 Wild

5/3/2018 2018-0018 Female 6 2 Wild


5/15/2018 2018-0020 Female 5 1 Wild

5/15/2018 2018-0021 Male 4 1 Wild

4/12/2018 2018-0102 Female 5 2 Larvae


4/12/2018 2018-0104 Male 5 2 Wild





4/12/2018 2018-0109 Female 6 2 Wild

4/12/2018 2018-0110 Male 6 2 No Sample


4/12/2018 2018-0112 Male 5 1 Wild

4/12/2018 2018-0113 Male 5 0 Wild


5/3/2018 2018-0164 Female 6 2 Wild

5/9/2018 2018-0171 Male 3 0 Wild

Table 14. 2018 Maryland Department of Natural Resources electrofishing survey Patapsco River Hickory Shad

spawning attempt composition for 2018.

Spawning Attempts

Sample

Year

Sample

Size (n)

1

Virgin

Spawners

2 3 4 5 6

2018 36 11

(31%)

7

(19%)

18

(50%)

0

(0%)

0

(0%)

0

(0%)

Table 15. 2018 Maryland Department of Natural Resources brood fish collections. Susquehanna River Hickory

Shad spawning attempt composition for sample years 2004-17.

Spawning Attempts

Sample

year

Sample

Size (n)

1

Virgin

Spawners

2 3 4 5 6 7

2004 80 25

(31%)

11

(14%)

17

(21%)

20

(25%)

6

(8%)

1

(1%)

2005 80 14

(18%)

10

(13%)

22

(28%)

25

(31%)

7

(9%)

2

(3%)

2006 178 58

(33%)

29

(16%)

48

(27%)

29

(16%)

11

(6%)

3

(2%)

2007 139 29

(21%)

26

(19%)

40

(29%)

23

(17%)

17

(12%)

3

(2%)

1

(1%)

2008 149 24

(16%)

37

(25%)

50

(34%)

29

(19%)

7

(5%)

2

(1%)

2009 118 13

(11%)

19

(16%)

54

(46%)

20

(17%)

11

(9%)

1

(1%)

2010 240 59

(25%)

72

(30%)

73

(30%)

25

(10%)

10

(4%)

1

(0.4%)

2011 216 67

(31%)

65

(30%)

57

(26%)

19

(9%)

6

(3%)

2

(1%)

2012 200 72

(36%)

64

(32%)

45

(23%)

15

(8%)

4

(2%)

2013 193 73

(38%)

62

(32%)

41

(21%)

15

(8%)

2

(1%)

2014 100 41

(41%)

19

(19%)

30

(30%)

10

(10%)

2015 113 46

(41%)

41

(36%)

21

(19%)

5

(4%)

2016 120 35

(29%)

38

(32%)

36

(30%)

10

(8%)

1

(1%)

2017 60 15 19 20 5

(25%) (32%) (33%) (8%)

2018 40 19

(48%)

13

(33%)

5

(13%)

3

(8%)

Figure 1. Maryland Department of Natural Resources 2018 target tributary for shad restoration project.

Figure 2. Maryland Department of Natural Resources 2018 Hickory Shad broodstock collection site on the

Susquehanna River.

Figure 3. Maryland Department of Natural Resources participating fish culture facilities in the restoration project.

GenOn Energy Chalk Point is a power company that cultures fish for the restoration effort. The University of

Maryland Center for Environmental Science Aquaculture and Restoration Ecology Laboratory (UMCES-AREL)

Figure 4. Maryland Department of Natural Resources tank spawn fertilization rates for Hickory Shad, 1996-2018.

Figure 5. Maryland Department of Natural Resources annual Hickory Shad stocking production in all tributaries,

1996-2018. The juvenile category includes fish stocked as early juveniles (late June) and late juveniles

(July/August). Fish were stocked into the Choptank River, Patuxent River, Nanticoke River, Patapsco River, and

Chester River.

Figure 6. Maryland Department of Natural Resources Patapsco River stocking sites in 2018.

Figure 7. Maryland Department of Natural Resources adult Hickory Shad electrofishing survey starting and ending

locations sampled on the Patuxent River and Choptank River.

Figure 8. Maryland Biological Stream Survey 2018 electrofishing survey sites on the upper non-tidal freshwater

portion of the Patapsco River.

Figure 9. Maryland Department of Natural Resources 2018 electrofishing survey sites on the lower tidal freshwater

portion of the Patapsco River.

Figure 10. 2018 Maryland Department of Natural Resources electrofishing collections and observations of adult

Hickory Shad in the Patapsco River.

hickory shad restoration in three maryland rivers · 2020. 7. 29. · hickory shad restoration in...

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